In electrical circuits, and particularly integrated circuits (ICs), there is often a need to provide stable reference voltages and reference currents for use throughout the IC. These reference circuits attempt to provide stable and known voltages that vary little over time and temperature variations.
One such type of reference circuit is known as a cross-coupled bandgap circuit. Cross-coupled bandgap circuits are often used in operational amplifiers, voltage regulators, phase locked loops (PLLs), and other devices requiring a VCC insensitive reference generator.
Problems with many conventional cross-coupled bandgap circuits include that they are often times sensitive to low frequency noise on the VCC line, are temperature unstable, have varying reference voltages as the VCC varies between a low and high operating voltage.
There is desired an improved reference circuit, such as a cross-coupled bandgap circuit, that is temperature stable, VCC insensitive, and minimally effected by VCC sources having noise or voltage spikes thereon.